This invention relates to a release agent and more particularly to a release agent that can be dispensed without the need of an aerosol propellant. The release agent is further characterized as employing a lecithin in combination with an oil base and has both food and industrial usages.
In the past, lecithin has been commercially marketed as a pan release agent and packaged in aerosol containers wherein much of the total product is the propellant/solvent system which evaporates to the atmosphere upon use. Flurocarbons have been the propellant/solvents primarily employed. Considering the possible harmful effects of flurocarbons on the ozone layer, there is a trend away from their usage. Even the other aerosol propellant/solvent such as low molecular weight hydrocarbons with carbon dioxide or nitrous oxide have been considered undesirable because of the possible danger from fire or explosion.
One attempt to avoid all these difficulties has been the development of a water based modified lecithin as found in U.S. Pat. No. 3,928,056. This has proved satisfactory for some usages but is characterized by a somewhat "soapy" flavor resulting from the modified lecithin and therefore does not provide optimum characteristics.
It would therefore be desirable to provide a release agent which could be mechanically dispensed (and therefore eliminate all the problems of the previously employed aerosols) yet one which would be optimal in organoleptic properties (if used for food purposes) as well as being stable. By stability, we refer not only to the resistance of the agent to separate into layers but also its ability to avoid smoke generation when applied to a heated surface. This pertains not only to the food usage as a pan release agent but to industrial usages such as in rubber molds, cutting oils, etc.
Besides the problems of taste and stability, another problem exists with utilizing lecithin in an aerosol-free dispenser -- the need for a solvent because of the high viscosity of the lecithin, even when oil based. Even an alcohol solvent (notably ethanol when a food usage is indicated) cannot provide proper solubility for either lecithin or a lecithin-vegetable oil mixture -- in particular, the class of vegetable oils known as oleic-linoleic acid oils or triglycerides composed of the triglycerides of predominately 16 to 18 carbon atoms of fatty acids also are not soluble in alcohol. Such vegetable oils of this classification usually include those of the soybean, peanut, cottonseed, safflower and sunflower and which can be used to dilute commercial lecithin. Although lecithin derived from soybeans is preferred, other vegetable sources may be utilized.
We have discovered that the lecithin-vegetable oil and alcohol can be brought into a stable solution system when these ingredients are augmented by other oils or modifications thereof which are generally classified as lauric acid oils where the fatty acids are predominately of the 6 to 12 carbon atom variety. Examples of such oils that exhibit partial or total solubility in alcohol are coconut, cohune, murumru tallow, palm kernel, tucum, ucuhuba tallow as either the glycerol esters or propylene glycol esters of the short chain fatty acids primarily in the range of C.sub.6 to C.sub.12. Also included are fractionated portions of these oils which result in higher C.sub.6 to C.sub.12 fatty acid concentrations and esterified triglycerides and propylene glycol wherein the replacement fatty acids are in the C.sub.6 to C.sub.12 range. These compounds can be used as the mutual solvent to dissolve lecithin, vegetable oils of the oleic acid class, the ethyl alcohol.
As a generic reference for the above identified materials we employ the term tri-glycol ester wherein the fatty acid chains have from 6 to 12 carbon atoms. Also, to refer to the vegetable oil ingredient, we use the same term but designate that the fatty acid chain has from 16 to 18 carbon atoms. For convenience we refer to the lower carbon atom tri-glycols as "lauric" and the higher "oleic".
With the combination of lecithin, alcohol and the two types of tri-glycol esters, we are able to improve taste, avoid separation, optimize viscosity and cost and to elevate the smoke point.
Other objects and advantages of the invention may be seen in the details set forth in the ensuing specification.